The Milbanke Sound cones are an enigmatic group of five small young volcanic cones in the Milbanke Sound area: Kitasu Hill, Helmet Peak, Price Island, Dufferin Island, and Finngal Island. Minimal erosion indicates all five volcanoes formed after the last glaciation, so they are probably less than 10,000 years old. Little is known about these cones, and their relationship to each other and to other British Columbia volcanoes is unclear; they are here grouped with the Anahim Volcanic Belt volcanoes based on their location, but because they are significantly younger than other volcanoes at the west end of the Anahim Volcanic Belt, the hotspot model most commonly used to describe the Anahim Volcanic Belt cannot be used to explain their formation. It is possible that the Milbanke Sound cones reflect a northern extension of the Garibaldi Volcanic Belt, or they may result from other crustal processes that are not yet understood.

The best preserved volcano in the Milbanke Sound group is Kitasu Hill, a symmetrical pyroclastic cone rising above the southern shore of Swindle Island to a crescent-shaped summit crater at an elevation of 250 m. It consists mainly of subaerial tephra and volcanic bombs enclosing remnants of olivine basalt flows.

Helmet Peak, on Lake Island, is a steep-sided mound of volcanic material rising from sea level to an elevation of 335 m. It comprises a pile of welded (cemented together by heat) volcanic blocks and basalt feeder dikes. Basaltic tuff breccia (a rock made up of volcanic fragments) derived from Helmet Peak covers parts of Lake Island and adjacent Lady Douglas Island.

Small basalt cones are present on Price Island and Dufferin Island. The cones themselves are covered by forest, but both cones have erupted lava flows that extend down to their shorelines.

Finngal Island is a small island south of Dufferin Island. It has one or more black lava flows with well-developed columnar jointing. Very little is known about these deposits.